This application claims the benefit of Korean Application No. 2002-23992, filed May 1, 2002, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates, in general, to air conditioners and, more particularly, to a multiunit-type air conditioner having a plurality of indoor units and used for heating or cooling indoor air, and to a method of detecting a refrigerant leakage in the air conditioner.
2. Description of the Related Art
Air conditioners are machines that control the indoor temperatures by transferring heat between refrigerant and indoor/outdoor air. FIG. 1 is a schematic view showing a construction and refrigerant flow of a conventional air conditioner, in which arrows show a refrigerant flowing direction during a cooling mode operation of the air conditioner. As shown in FIG. 1, the conventional air conditioner comprises an indoor unit 102 and an outdoor unit 104, with an indoor heat exchanger 116 installed in the indoor unit 102. The indoor heat exchanger 116 is a device at which heat is transferred between the refrigerant and indoor air. The indoor unit 102 also has an indoor expansion valve 114 which regulates pressure of the refrigerant flowing to the indoor heat exchanger 116 during a cooling mode operation. Two or more indoor units 102 each having the above-mentioned construction may be arranged in parallel as desired to form a multiunit-type air conditioner.
The outdoor unit 104 comprises an outdoor heat exchanger 122 and a compressor 118. The outdoor heat exchanger 122 is a device at which heat is transferred between the refrigerant and outdoor air. The compressor 118 sucks low temperature and low pressure refrigerant, and compresses the low temperature and low pressure refrigerant to make high temperature and high pressure refrigerant prior to discharging the refrigerant from the compressor 118. The outdoor unit 104 also has an outdoor expansion valve 128 which regulates pressure of the refrigerant flowing to the outdoor heat exchanger 122 during a heating mode operation. A four-way valve 130 is mounted on a refrigerant circulating line in the outdoor unit 104, and controls a flowing direction of an output refrigerant from the compressor 118 such that the output refrigerant flows to the outdoor heat exchanger 122 or the indoor heat exchanger 116 in accordance with a selected mode of the air conditioner.
Extending between the indoor unit 102 and the outdoor unit 104 of the air conditioner is the refrigerant circulating line (refrigerant pipe) which guides the flow of the refrigerant between the indoor unit 102 and the outdoor unit 104. Particularly in the case of a multiunit-type air conditioner having a plurality of indoor units 102, the refrigerant pipe is very long in length and somewhat complex in construction, and so by integrating a plurality of short pipes having an easily-handled length to each other to form a long and complex refrigerant pipe through, for example, a welding process is necessary. However, when the welding process is not effectively or sufficiently performed at welded junctions of the refrigerant pipe or when the refrigerant pipe is not properly managed after an installation of the pipe in the air conditioner, the refrigerant pipe may be broken at the welded junctions and undesirably allow a refrigerant leakage through the broken junctions. Further, repeated operation of the air conditioner over a lengthy period of time causes the refrigerant pipe to gradually become fatigued, and, in such a case, the refrigerant pipe may be loosened at connected junctions of the refrigerated pipe, thus allowing a refrigerant leakage through the loosened junctions. When the refrigerant leakage from the refrigerant pipe occurs, the air conditioner cannot perform an operation of the air conditioner. Therefore, in such a case, a user of the air conditioner must find positions of broken or loosened junctions of the refrigerant pipe to quickly repair the refrigerant pipe and restore a desired operation of the air conditioner.
The refrigerant leakage from the refrigerant pipe of an air conditioner has been detected by checking a variation in pressure of the output refrigerant from the compressor. However, this method only informs a user of an occurrence of the refrigerant leakage from the refrigerant pipe, but does not allow the user to find exact positions of the broken or loosened areas of the refrigerant pipe, and so the user cannot easily or quickly repair the broken or loosened refrigerant pipe. In the case of a multiunit-type air conditioner having a very long and complex refrigerant pipe, to find the exact positions of the broken or loosened areas of the refrigerant pipe is more important than to detect an occurrence of the refrigerant leakage from the refrigerant pipe. However, to find the exact positions of broken or loosened areas of the long and complex refrigerant pipe is very difficult. Particularly, in the case of a building with a centralized air conditioning system, the refrigerant pipe of an air conditioning system is typically installed in the building at the same time as constructing the building such that the refrigerant pipe is hidden in walls, ceilings and floors. Therefore, to find the exact positions of the broken or loosened areas of the pipe in the case of a refrigerant leakage is even more difficult.
Accordingly, an air conditioner and a method of detecting a refrigerant leakage in the air conditioner are provided, in which an entire refrigerant pipe of the air conditioner is sectioned based on expansion valves into a plurality of sections, and the sections are checked one by one to quickly detect a refrigerant leakage from the sections, as well as to find an exact position of a broken or loosened area of the refrigerant pipe causing the refrigerant leakage.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
In order to accomplish the above and other aspects, the present invention provides an air conditioner, comprising a compressor, an expansion valve, an outdoor heat exchanger, and an indoor heat exchanger connected to each other by a refrigerant pipe, wherein the refrigerant pipe is sectioned into a high pressure section extending from an outlet port of the compressor to an inlet port of the expansion valve, and a low pressure section extending from an outlet port of the expansion valve to an inlet port of the compressor. In the air conditioner, the control unit detects a refrigerant leakage in the low pressure section by comparing a variation in refrigerant pressure, sensed by a pressure sensor provided on the refrigerant pipe within the low pressure section, with a preset variation in the refrigerant pressure in the case of a normal operation without having a refrigerant leakage, during a refrigerant leakage detection mode.